Reference is now made to the prior art drawing of FIG. 1 illustrating a double twin-tube fluorescent lamp assembly as a presently in manufacture. The fluorescent lamp may be of the type manufactured by GTE Products Corporation, either the 9 watt lamp identified by Sylvania Model No. F9DTT/27K or the 13 watt version identified by Sylvania Model No. F13DTT/27K. A similar constructuon is also used in the twin-tube fluorescent lamp. These may be the type presently manufactured by GTE Products Corporation under Sylvania model Nos. F9DDT/27K (9watt) and F13DTT/27K (13watt).
In the prior art drawing of FIG. 1, the fluorescent lamp is comprised of the double twin-tube bulb as illustrated at 10 and is provided with the typical jointing connection as indicated in dotted outline at 12. Associated with the bulb 10 are a pair of filaments, only one of which is illustrated in FIG. 1 at 14. The filament 14 has coupled therefrom lead wires 16 and 18.
The double twin-tube bulb 10 is supported in the two-part base that is comprised of a base shell 20 and base bottom 22. The double twin-tube bulb 10 is secured in the base shell 20 by means of an appropriate cement such as is illustrated at 24 in FIG. 1.
FIG. 1 also illustrates the pins 26 and 28 that are supported from the base bottom. The glow bottle 30 and capacitor 32 comprising the starter circuit are contained within the base bottom 22. With regard to the pins 26 and 28, it is noted that one of the filament wires 16 from the filament 14 is staked into the pin 26 while a lead wire 17 coupled from the other filament is captured and staked at the other pin 28. It is noted that in the prior art fluorescent lamp construction of FIG. 1, clamps are employed as illustrated schematically at 34 and 36. These clamps are used to tie together lead wires for electrical connection between the various components, and in particular for connection between the glow bottle 30, capacitor 32, and lamp filaments. In this regard, note that one of the lead wires 18 from the filament 14 couples to the clamp 36. A lead wire covered by insulator sleeve 38 also couples from the other filament to the clamp 34.
In addition to the requirement of the use of clamps as illustrated at 34 and 36 in FIG. 1, there also have to be provided, insulator sleeves 38 and 40. These sleeves are used to prevent electrical shorting of leads. As indicated previously, the lamp starter components are encapsulated in the two-part base with the two lead wires from the respective lamp filaments being inserted into the pins 26 and 28 and staked to complete the assembly.
One of the disadvantages associated with the prior art construction of FIG. 1 is the relatively large number of separate components that are necessary. In addition to the basic required starter components, this prior art construction also required clamps and insulator sleeves.
Another disadvantage with the prior art constructuon of FIG. 1 is that the lead wires are too long, particularly when considering use in automated processing. Because of the use of several different length lead wires, there is also a danger in having lamp short circuits. Also, the lengthy leads can provide bending and breakage problems that are inherent with long wires.
A further disadvantage of the prior art construction of FIG. 1 is that the assembly of the lamp is expensive to implement. This is primarily because of the number of components and their complexity of assembly. This limits the speed of production and thus means that the manufacturing cost is higher. The maximum speed of production is about 1000 lamps per hour. The manufacturing efficiently is low and more skilled and unskilled labor is required to service the manufacturing of the product. Ultimately, this means that the product cost to the customer is relarively expensive employing the construction of FIG. 1.
Reference is also made to U.S. Pat. No. 4,426,602. This patent describes a low pressure mercury vapor discharge lamp which is also of prior art construction employing some form of lead interconnection between the filaments and starter circuit.